Brake



H. c. BOWEN 2,223,546 v BRAKE Filed Dec. 3, 1938 I luunun lnwuln,

INVENTOR.

{fa-8557 C Hams-xv.

ATTORNEY.

Patented Dec. 3; 1940 PATENT OFFICE BRAKE Herbert 0. Bowen, Detroit,Mich., assignortollydraulic Brake Company, Detroit, Mich, a corporationof California Application December 3,1938, Serial No.'243,864

6 Claims.

This invention relates to brakes, and more particularly to brakes formotor vehicles.

Broadly the invention comprehends a motor vehicle brake of the internalexpanding type including a pair of corresponding interchangeablefriction elementsor shoes so connected and mounted as to preserveuniformity of action and controllability of the anchored shoe in onedirection of braking, and to function as a conventional duo-servo brakein the other direction of braking. Anobject of the invention is toprovide a brake structure operative to function as a link brake onedire'ctionof braking, and as a duo-servo brake in the other direction ofbraking.

Another object of the invention is to provide a. brake including a. pairof corresponding interv changeable friction elements or shoes soanchored and connected as to increase effectiveness of the anchored shoein both forward and. reverse braking.

Another object of the invention is to provide a brake including a pairof shiftably mounted friction elements or shoes so connected andactuated that the applied actuating force, augmented by the wipingaction of the drum, may be partly transmitted from the forward brakingshoe to the reverse braking shoe to the end that the brake may berendered more efiective. Other objects and advantages of the inventionwill appear from the following description taken in connection with thedrawing forming a part of this specification, and in whichtaken justback of the head of the drum illus trating the invention as applied; and

Fig. 2 is a sectional view taken substantially on line 2-2, Fig. 1.

Referring to the drawing for more specific details of the invention, IIIrepresents a fixed support or backing plate adapted to'be secured to anaxle or to an axle housing. A rotatable drum 12 associated with thebacking plate is adapted to be secured to a wheel, and a pair ofcorresponding interchangeable friction elements or shoes I4 and [6 aremounted on the backing plate forcooperation with the drum.

Each of the shoes includes a web [8 supporting a rim 20 having suitablysecured thereto a lining 22. The shoes are mounted on diametricallydisposed anchors 24 and 26 arranged on the backing plate l0, and. aretractile stop 28 also arranged on the backing plate serves to supportthe shoes, when in retracted position, in

Fig. 1 is a vertical sectional view of a brake proper spaced relation tothe drum. The shoes are shiftably mounted on the anchors 24 and 26. Asshown, the anchor 24 supports the toe of the forward braking shoe M, andthe anchor 26 supports the heel of the trailing or reverse braking shoel6.

An adjustable link 30' connects the forward braking shoe to the trailingor reverse braking snoe adjacent the heels of the respective shoes. Theshoes are also connected by a retractile 10 spring 32, and the forwardbraking shoe is connected by retractile springs 34 and 36 to fixedsupports 38 and 4B suitably arranged on the backing plate. The spring 32serves to return the shoes upon completion of a braking oper- 15 ationto their retracted position on the stop 28, the spring 34 serves to liftthe forward braking shoe l4 against the anchor 24, and the spring 36serves to hold the reverse braking shoe on the 20 anchor 26.

An operating means for the shoes includes a fluid pressure actuatedmotor 42 of conventional type secured to the backing plate and suitablyconnected to the toes or force applying ends of 25 the respective shoes.

In a normal operation, during a forward braking application, uponenergization of the motor 42, the shoes I4 and I6 are moved from theirretracted position into engagement with the drum 80 I2. In effectingthis actuation of the shoes, the forward braking shoe l4 moves from itsanchor 24 and is slightly shifted by the wiping action of the drum, andthe trailing or reverse braking shoe pivots on its anchor 26. Theapplied force on the forward braking shoe I4 is augmented by the servoaction of the shoe l4, and a part of the combined braking force of theshoe [4 is transmitted from the forward shoe [4, through the link 30, tothe heel of the trailing or reverse brakingshoe, so as to increase theefiectiveness' of the trailing or reverse braking shoe.

On a reverse braking application, the trailing or reverse braking shoel6 becomes the forward braking zishoe, and the forward braking shoe M 45becomes the reverse braking shoe. Under this condition, the shoe Itmoves from its anchor 26 and is slightly shifted by the wiping action ofthe drum, while the shoe [4 pivots on its anchor 24. 5 The applied forceon the shoe I6, augmented by the wiping action of the drum, is nowpartly transmitted through the link 30 to the toe of the shoe It, so asto increase the efiectiveness of the shoe M, the shoe I6 functioning asa servo shoe 5 reversed by simply reversing the brake asawholel 1 or byreversing" the anchors for the res pective shoe.

While this invention has been described in connection with certainspecific embodiments, the

principle involved is susceptible of numerous 7 other applications thatwill readily, occur to per.-

sons skilled in the-art. The invention is,therefore, to be limited onlyas indicated by the scope of the a pended claims.

1 Having thus described the various features of the invention, what Iclaim as new and desire to secureby Letters Patent is- 1. A brakecomprising a fixed support,=-a pair of anchors diametrically disposed onthe support,

. a pair of, shoes shiftably mounted on the anchors in tandem, and alink connecting the shoes within ,the radius of one of the anchors.

2. A brake comprising a fixed support, avpair of anchors diametricallydisposed on the support, a pair of shoesshiftably mounted on the anchorsin tandem, an adjustable link connecting the unanchored end of one of,the shoes to the anchored end of the other shoe within the radius of oneof the anchors and means for actuating the shoes. n

3. A brake comprising a. fixed support, a rotatable drum associatedtherewith, a pair or anchors diametrically disposed on the support, apair. of shoes shiftably mounted on the anchors in tandem, a linkconnecting the unanchored end of one of the shoes to the anchored end ofthe other shoe withinthe radius of one of the anchors, and a fiuidpressure actuated motor con3- nected to the anchored end of one of theshoes 5 and the unanchored end of the other shoe.

. 4. A brake comprising a fixed suppont, ;a, rotatable driirmassociatedtherewith, alfpair Qfianchors diametrically disposedon the support, apair of corresponding shoes shiftably mounted on the anchors, anadjustable link connecting the un-, anchored end of one of the shoes tothe anchored end of the otherishoewithin the radius of one oftheanchora',andahneansfor actuating the shoes. 5. A brake comprising afixed support, a rotatl5 .able drum associated therewith, a pair ofanchors "diametricallydisposed-onthe fixed support, a pair .of,corres ponding interchangeable shoes shiftably mounted on the anchors in tandem,an adjustable link connecting one of thshoesadjacent new anchored end tothe'other shoeadjaceiitfits'am chored'end, and a'motor' for actuatingthefsho connected between the anchored end or'one'or the shoesand'the'unanchored end'ofthe other she 6. A brake comprising a'fixedsupport, 'a 'r'otat- 25 able drum associated-therewith, a; pair'fofanchor diametrically disposed on-the fixed support, a pair of shoesshiftably mounted on theanchors in tandem for. cooperation "with thedru'm,"means" connecting the shoes for transmitting forcefrom"80 theunanchored. end of oneof -the' shoes to'the' anchoredend of the othershoe in one direction'of braking and from the anchoredend of one 'of theshoes to the unanchored end of the other shoe in the other direction ofbraking, and means forv tuating-the shoes; 9 1: 1: v

JHERBERTQBQWENJ

